64 UNIVERSITY OF COLORADO STUDIES 



the brain allowing the formation of such habits and associations. 

 Many plays are acquired work activities which have gradually be- 

 come modified into play.^ 



According to the law of increase of plasticity it is manifest that 

 instincts tend to become weakened into impulses, and that as we 

 come up the zoological scale instincts tend to become less rigid and 

 organisms to become congenitally weaker and weaker. As the organism 

 becomes weaker it grows in plasticity. As organic heredity weakens, 

 social heredity increases and accumulates. So, in reference to play, 

 it can be easily shown that these adult ancestral occupations and 

 these youthful modifications of them are acquired characteristics, 

 connected though they may be, directly or indirectly, with native 

 impulses. 



If play were as Groos defines it, the manifestation {^Ausueh- 

 ung') of instinct and the development {Einuebung) of the complete 

 instinct, then there would be little if any advance beyond the inher- 

 itance provided for us by organic heredity. We should be still lim- 

 ited to the instinctive life of the past. No increase in plasticity or 

 adjustability would result. If, on the other hand, the increase of 

 plastic endowment weakened the instincts to impulses, as it actually 

 does, then newer and other reactions could he grafted on the in- 

 herited impulses. Here comes in the important role of play, for ly 

 means of play social occupational activities are attached to native 

 impulses and take the place of the older instincts. The young are 

 thus prepared better for life. The rejuvenescence and development 

 of old instincts is thus obviated, at least to some extent. The new 

 reactions would represent greater adjustability and growth in intelli- 

 gence. In the Groos theory growth in intelligence is claimed, but the 

 modus operandi of such growth is not to be found in the develop- 

 ment of inherited impulses into their former state as instincts. 



Spencer, Strieker, Wundt, Baldwin, Schneider, Groos and others 

 speak of an instinct of imitation and an instinct of play. To speak 

 of the impulse to imitate and to play is not much improvement on 

 the doctrine. There is no such general instinct or impulse to play. 



•Karl Buecher, Arbeit und Rhythmus, Leipzig, 1899, 2te Aufl., passim. 



